You might try a pair of Comtrend G.hn powerline adaptors. They claim their G.hn communications protocol is more noise-resistant.
I never got anywhere near the blazing speeds Comtrend suggests you can get with them, but I did get a minimum of a solid 80mb/s or better throughout the house, even going worst-branch-circuit-to-worst-branch-circuit, across the phase split, and 70mb/s to the shed--about 100 ft. from the house. That's more than enough for a couple IP cams. There's a GFCI and arc fault breaker on that branch for the shed, too.
